Scroll-type expander having heating structure and scroll-type heat exchange system employing the expander

ABSTRACT

The present invention provides a scroll-type expander that simultaneously performs expansion and re-heating such that efficient expansion is realized and there is no reduction in efficiency caused by pressure loss occurring during the supply of an working fluid to the scroll-type expander, and that minimizes a difference in temperature between a stationary scroll member and a rotating scroll member, as well as a temperature distribution of a scroll wrap. The present invention also relates to a heat exchange system that uses a scroll-type expander to replace pistons in a conventional reciprocating Stirling engine or refrigerator with a pair of scroll-type compressor and expander such that the heat exchange system may be used as a Stirling engine or refrigerator. The present invention also provides a steam engine, in which a steam turbine in the conventional steam engine (Rankine system) is replaced with a scroll-type expander such that the steam cycle has both a re-heating cycle and a regeneration cycle.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to a scroll-type expander and ascroll-type compressor, and more particularly, to a scroll-type expanderand a scroll-type compressor that include a stationary scroll member anda rotating scroll member to continuously perform expansion andcompression of an working fluid. The present invention also relates to ascroll-type heat exchange system that includes a scroll-type expanderand scroll-type compressor for use as a Stirling engine or refrigerator.

(b) Description of the Related Art

Scroll device offers many advantages including high efficiency, lownoise, low vibration, small size, and light weight. Scroll devices arewidely used as a result of these advantages scroll-type compressor Inmore detail, with reference to FIG. 1, a stationary scroll member 30 ofinvolute form and a rotating scroll member 40 are provided at a 180°phase difference. As a result, a series of crescent-shaped pockets areformed within the scroll-type compressor. Gas flows into the scroll-typecompressor through an intake passage located at a circumference of thestationary scroll member 30, and the crescent-shaped pockets move towarda center of the two scrolls 30 and 40 by the orbiting action of therotating scroll member 40. A volume of the pockets is reduced throughthis operation such that the gas is compressed. The gas is thendischarged through a discharge port formed in a center of the stationaryscroll member 30. During each orbit, several crescent-shaped pockets arecompressed simultaneously, so operation is continuous.

In the scroll-type expander, the scroll-type compressor is simplyoperated in reverse such that a gas is expanded. That is, a highpressure gas is provided to the center of the stationary scroll member30 such that the orbiting scroll member 40 is displaced to realizeexpansion of the gas, which is then discharged through thecircumferential opening of the stationary scroll member 30. Motive poweris generated by the orbiting motion of the rotating scroll member 40.

Compared to other types of compressors, the scroll-type compressorrequires less parts, is small and lightweight, and provides otheradvantages such as high efficiency, low vibration, and low noise. As aresult, the scroll-type compressor is widely used as a refrigerantcompressor and air compressor. The scroll-type expander, on the otherhand, has not experienced widespread use.

As a conventional expander, U.S. Pat. No. 4,192,152 discloses a scrollapparatus with peripheral drive that can be used as a compressor and anexpander, and a heat engine that combines a compressor, a burner, and anexpander, and also discloses a Brayton cycle-type cooling cycle thatcombines a compressor and an expander. Also, EP Patent No. 0846843A1discloses a heat engine that combines a compressor, a regenerator, aburner, and an expander. In addition, there has also been recentlydisclosed in the United States a steam cycle (Rankine system) that usesa scroll-type expander in place of a steam engine.

However, in patents and research related to scroll-type expandersdisclosed up to now, high pressure gas or steam is supplied to a centerarea of the scroll-type expander to generate motive power as inconventional turbines. As a result, efficiency is reduced by pressureloss when supplying the gas or steam such that while compressionefficiency reaches up to 90%, expansion efficiency is only about 60˜70%.Further, in the conventional scroll-type expander, a difference intemperatures between the stationary scroll member and the orbitingscroll member develops, and a temperature gradient occurs within thesame scroll wrap itself. These factors result in a reduction inefficiency by the generated friction, leakage, and increased vibration.

A Stirling engine is an external combustion engine that includes aplurality of heat exchangers that heat and cool the enclosed charge gas.Most Stirling engines are external combustion engines of reciprocatingpiston types.

Because the Stirling engine is an external combustion engine, it may usevarious heat sources such as liquid fuel, gas fuel, solid fuel,industrial waste energy, solar energy, and LNG. The Stirling engineprovides high efficiency due to a regenerator mounted between a heaterand a cooler. Also, because the Stirling engine does not include valvesand realizes smooth pressure changes, a low level of noise and vibrationare generated compared to the internal combustion engine. Also, sincecontinuous combustion occurs in the Stirling engine, combustion controlis easy and the exhaust gas is relatively clean, thereby making theStirling engine a possible candidate for widespread use in the future.

With reference to FIG. 8, which shows a basic structure of aconventional Stirling engine 200, an expansion piston 201 and acompression piston 203 are coupled to a common crankshaft with about 90°phase difference. An expansion space 205 and a compression space 207 areformed and connected to a regenerator 209 that is filled with thermalenergy storage material having gas permeability. With thisconfiguration, since it is difficult to realize sufficient heating andcooling of the working gas by a cylinder wall of a small heat transferarea, a cooler 212 and a heater 214 are provided to opposite sides ofthe regenerator 209 as shown in FIG. 9.

To simplify the mechanical structure and reduce vibration of thereciprocating-I Stirling engine, U.S. Pat. No. 6,109,040 discloses aconfiguration that uses two rotary Wankel rotors and provides for aphase difference as in the reciprocating Stirling engine such thatcompression and expansion are alternatingly realized.

Since two pistons reciprocate in cylinders synchronously but out ofphase so that the working gas shuttles cyclically from one space to theother as the volume and pressure vary from maximum to minimum and gothrough the four processes of the Stirling cycle in order, the workingfluid undergoes pressure loss due to the oscillating flow through theregenerator positioned between the compression cylinder and theexpansion cylinder such that an increase in rotational speed results inthe reduction in torque. In addition, because it is difficult to realizesufficient heating and cooling of the working gas by a cylinder wall ofa small heat transfer area, the cooler 212 and the heater 214 areprovided to opposite sides of the regenerator 209 as shown in FIG. 9,and it is necessary to use a gas having a low molecular weight such ashydrogen or helium as the working gas. However, in the case where a gasof a low molecular weight is used as the working gas, leakage easilyoccurs such that it is extremely important to use a high performance gasseal.

With reference to FIGS. 10 and 11, an ideal Stirling cycle includesisothermal compression (I–II) while in a low temperature compressionsection 223, constant volume heating (II–III) while passing aregenerator 221, isothermal expansion (III–IV) while in a hightemperature expansion section 224, and constant volume heat rejection(IV–I) while passing the regenerator 221. However, the actual cycle ismore like that shown in FIG. 12, which is significantly less efficientthan the ideal case. The reasons for such a difference between an idealStirling cycle and the actual cycle, and the difficulties in realizingthe ideal cycle, will be described as follows.

First, to realize the isothermal compression (I–II) and isothermalexpansion (III–IV) sections of the ideal Stirling cycle, fast heattransfer must occur through the inside surface of the cylinder walls.However, even if a sufficient number of heat transfer pins are mountedoutside the cylinder, since the area of the inside surface of thecylinder walls making contact with the working gas is limited, it isdifficult for the working gas to be heated or cooled isothermally. Thisbecomes increasingly problematic if the engine is made faster and tolarger sizes, in which case the processes inside the cylinder becomesmore adiabatic (no heat transfer) than isothermal (infinite heattransfer).

It is for this reason that the additional heater 214 and cooler 212 aremounted to opposite ends of the regenerator 209 to ensure effectiveheating and cooling of the working gas. Although the heater 214 andcooler 212 allow for the effective heating and cooling of the workinggas to increase the specific power, the provision of such heatexchangers imposes some penalties as follows.

In particular, the increase in dead volume, which includes the heater214, the regenerator 209, and the cooler 212, acts to decrease output.Further, it results in anomalies in which the expanded working gas picksup heat from the heater 214 before deposing its heat in the regenerator209 and in which the compressed gas has to pass through the cooler 212before going back through regenerator 209 to pick up heat. As a result,the flow resistance is increased and thermal efficiency is reduced.Further, the thermal stress to the structural parts increases such thatcare must be given in selecting the materials for the parts and otherlimitations are given to manufacture of the device.

In the ideal Stirling cycle as shown in FIG. 10, since the motions ofthe pistons 225 and 227 are discontinuous, only compression occurs inthe low temperature compression section 223 and only expansion occurs inthe high temperature expansion section 224. However, in an actualreciprocating Stirling engine shown in FIG. 9, the compression piston203 and the expansion piston 201 are linked to move together such thatduring compression by the compression piston 203 of the low temperaturesection, compression occurs slightly also by operation of the expansionpiston 201 of the high temperature section. Likewise, during expansionby the expansion piston 201 of the high temperature section, expansionoccurs slightly also by operation of the compression piston 203 of thelow temperature section. This is another main reason why the efficiencyof the actual Stirling engine is significantly less than that of theideal Carnot engine.

The steam cycle includes four successive changes. These include heatingof the working fluid, evaporation, expansion, and condensation. TheRankine cycle is the ideal cyclical sequence of changes of pressure andtemperature of the working I fluid, and is used as a standard for ratingthe performance of steam power plants.

With reference to FIG. 13, a steam engine 300 typically includes a watersupply pump 303 (adiabatic compression), a boiler 305 and a re-heater307 (isobaric heating), turbines 309 and 312 (adiabatic expansion), anda condenser 301 (isobaric heat radiation). A steam turbine is mostcommonly used by a power output device in the steam engine that is usedas an external combustion engine. The steam turbine converts heat energyinto kinetic energy such that high speed steam strikes a turbine toobtain a rotational force of the same.

As a way to improve efficiency in the steam cycle, referring again toFIG. 13, the re-heater 307 is used and the steam in the expansion stageis extracted to the outside of the turbine 309 before being saturated,and is made into superheated steam after being heated in the re-heater307. The steam is again directed to the turbine 312 to use a re-heatingcycle that expands the steam until reaching the output pressure. Thermalefficiency may be improved by increasing the number of re-heatingstages. However, if the number of re-heating stages is increased, thefluid needs to be circulated between the boiler 305 and turbines 309 and312, both the overall size of the assembly and equipment costs areincreased, and operational control becomes complicated. Accordingly,re-heating is typically performed one or two times, which places alimitation on the efficiency of the steam cycle.

In the reciprocating piston or Wankel rotary device, which areconventional positive displacement expanders used as external combustionengines in place of the steam turbines 309 and 312, since the area ofheat transfer through the cylinder walls decreases compared to volume ascapacity is increased, efficiency reduces in proportion to increases insize of the device.

SUMMARY OF THE INVENTION

The present invention provides a scroll-type expander thatsimultaneously performs expansion and re-heating such that highlyefficient expansion that approximates isothermal expansion is realizedand such that there is no reduction in efficiency caused by pressureloss occurring during the supply of an working fluid such as gas orsteam to a center area of the scroll-type expander, and that minimizes adifference in temperature between a stationary scroll member and aorbiting scroll member, as well as a temperature distribution of ascroll wrap.

The present invention also relates to a heat exchange system that uses ascroll-type expander to replace pistons in a conventional reciprocatingStirling engine or refrigerator with a pair of scroll-type compressorand expander such that the heat exchange system may be used as aStirling engine or refrigerator.

The present invention also provides a steam engine, in which a steamturbine in the conventional steam engine (Rankine system) is replacedwith a scroll-type expander such that the steam cycle has both are-heating cycle and a regeneration cycle.

In one embodiment, the present invention provides a scroll-type expanderincluding a sealed housing having a heating surface to an outside area,and including at least one of each of an inflow opening and an exhaustopening at both a center area and a circumferential area; stationaryscroll members fixed within the housing and extending from the centerarea of the housing outwardly in a spiral shape; orbiting scroll membersmeshed with the stationary scroll members within the housing andextending from the center area of the housing outwardly in a spiralshape, the orbiting scroll members orbiting along a predeterminedorbiting radius to continuously expand working fluid entering thehousing; heating chambers provided to an outer circumference of thehousing and which supply heat when working fluid is expanded by themotion of the orbiting scroll members; and drive shafts connected to theorbiting scroll members to drive the scroll members.

The scroll-type expander may further include a pre-heating pipeconnected to the working fluid inflow opening of the center area of thehousing and extending into the heating chambers to pass through theheating chambers so that the working fluid entering the heating chambersmay absorb heat, and a plurality of heating pins formed to the externalheating surface of the housing that is located within the heatingchambers.

A power transmission shaft may be connected to an outside of one of thedrive shafts to enable the transmission of power to outside thescroll-type expander.

The scroll-type expander may further include heat pipes as a heattransfer assembly connected to the heating chambers and able to transmitlarge amounts of heat by the low temperature difference as a result oflatent heat.

The steam engine includes a scroll-type expander as described above; aheat exchanger through which high temperature working fluid expanded inthe scroll-type expander and exhausted from the scroll-type expanderpasses; a condenser for condensing the working fluid passing through theheat exchanger; a storage tank for storing the working fluid passingthrough the condenser; and a pump for pressurizing the working fluidpassing through the storage tank. The working fluid pressurized in thepump is circulated by again passing through the heat exchanger toreceive heat from high temperature heat source.

With the scroll-type expander of the present invention, heating,expansion, and re-heating take place in the expander itself such that acompact configuration is realized and isothermal expansion thatapproaches an infinite stages re-heating cycle is realized.

The scroll heat exchange system includes a scroll-type compressorincluding a sealed housing having a heat radiation surface and having atleast one of each of the working fluid inflow opening and an exhaustopening at both a center area and a circumferential area, a stationaryscroll member fixed within the housing and extending from the centerarea of the housing outwardly in a spiral shape, and an orbiting scrollmember meshed with the stationary scroll member within the housing andextending from the center area of the housing outwardly in a spiralshape, the orbiting scroll members orbiting along a predeterminedorbiting radius to continuously compress working fluid entering thehousing; a scroll-type expander including a sealed housing having aheating surface and having at least one of each of an working fluidinflow opening and an exhaust opening at both a center area and acircumferential area, a stationary scroll member fixed within thehousing and extending from the center area of the housing outwardly in aspiral shape, and an orbiting scroll member meshed with the stationaryscroll member within the housing and extending from the center area ofthe housing outwardly in a spiral shape, the orbiting scroll membersorbiting along a predetermined orbiting-radius to continuously expandworking fluid entering the housing; a driver connected to each of theorbiting scroll members of the scroll-type compressor and thescroll-type expander to drive the orbiting scroll members; a firstconnector interconnecting the working fluid exhaust and inflow openingsat the outer areas of the scroll-type compressor and the scroll-typeexpander; a second connector interconnecting the working fluid exhaustand inflow openings at the center areas of the scroll-type compressorand the scroll-type expander; a regenerator through which the first andsecond connectors pass in a state adjacent to one another to realizeheat exchange between the working fluid passing through the first andsecond connectors; and working fluid compressed in the scroll-typecompressor, exhausted through the exhaust opening at the center area ofthe scroll-type compressor, passed through the regenerator via thesecond connector, then supplied through the inflow opening at the centerarea of the scroll-type expander, after which the working fluidundergoes expansion in the scroll-type expander, is exhausted throughthe exhaust opening at the outer area of the scroll-type expander,passed through the regenerator via the first connector, and suppliedthrough the inflow opening at the outer area of the scroll-typecompressor to thereby realize circulation of the working fluid throughthe heat exchange system.

The scroll heat exchange system may further include a cooling sectionformed around an outer circumference of the housing that surrounds thescroll-type compressor such that heat generated when working fluid iscompressed is expelled outwardly, and a heating section formed around anouter circumference of the housing that surrounds the scroll-typeexpander such that heat is supplied during expansion of working fluid.

The scroll heat exchange system may further include a cooler connectedto the working fluid inflow opening provided to the outer area of thescroll-type compressor and acting to cool the working fluid that issupplied to the scroll-type compressor after passing through theregenerator, and a heater connected to the working fluid exhaust openingprovided to the center area of the scroll-type expander and acting toheat the working fluid that is supplied to the scroll-type expanderafter passing through the regenerator.

The scroll heat exchange system may further include a bypass linecommunicating an area between a center compression area of apredetermined distance from the center area of the housing and theconnector connected to the working fluid exhaust opening of the centerarea, and a control valve mounted on the bypass line to control theamount of fluid that is bypassed to vary compression amounts.

The scroll heat exchange system may operate as an engine when a heat ofa temperature higher than a temperature of the scroll-type compressor issupplied to the scroll-type expander, and power is output from thedrivers connected to the scroll-type expander and the scroll-typecompressor. Also, the scroll heat exchange system may operate as arefrigerator when power is input to the drivers connected to thescroll-type expander and the scroll-type compressor, and a heat of atemperature lower than a temperature of the scroll-type compressor isabsorbed in the scroll-type expander.

In the scroll heat exchange system of the present invention, themechanical structure is simple, and compression and expansion arecontinuously performed such that there is almost no variation in torqueand a flow direction of the operational fluid is unchanged. As a result,flow lines and regenerator structure may be realized such that flowresistance is small.

In addition, since the heat transfer area making contact with theworking fluid in the compressor and expander is extremely large, highlyefficient isothermal compression and expansion that approaches the idealStirling cycle is possible, and a heater and cooler may be made small orremoved altogether such that dead volume is reduced to improve output.Finally, overall manufacturing costs are reduced by minimizing orremoving the need for the heater.

In the scroll heat exchange system of the present invention, since theworking fluid flow is in one direction, the working fluid heated in theheater is not re-heated following expansion, and the working fluidcooled in the cooler is not re-cooled following compression such thatheat loss, flow resistance, thermal stress, etc. caused by anomalies inthe cycle may be reduced.

In addition, since low temperature compression and high temperatureexpansion are realized as fully separated processes, high efficiencythat approaches an ideal cycle may be obtained. Also, compression ratiocontrol by the bypass line in the compressor is easy such that effectiveengine control is possible.

Finally, in the scroll heat exchange system of the present invention,since continuous, steady state driving is possible, there are almost noperiodic temperature and pressure variations in the structural elementssuch that limitations on the selection of materials for and manufactureof the structural elements are significantly reduced, and low noise, lowvibration, small size, and light weight may be realized as a result.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic drawing showing the interaction between astationary scroll member and a orbiting scroll member, and is used todescribe an operation of a scroll-type compressor.

FIG. 2 is a sectional view of a scroll-type expander according to apreferred embodiment of the present invention.

FIG. 3 is a schematic view of a scroll heat exchange system according toa first embodiment of the present invention.

FIG. 4 is a schematic view of a scroll heat exchange system according toa first embodiment of the present invention with a cooler and a heaterattached thereto.

FIG. 5 is a sectional view of a scroll heat exchange system according toa second embodiment of the present invention.

FIG. 6 is a schematic view of a scroll heat exchange system according toa third embodiment of the present invention.

FIG. 7 is a schematic view of a scroll assembly connected to a bypassline according to a preferred embodiment of the present invention.

FIG. 8 is a schematic view of a conventional reciprocating Stirlingengine.

FIG. 9 a schematic view of a conventional reciprocal Stirling enginewith a heater and a cooler attached thereto.

FIG. 10 is a schematic view used to describe the sequential processes inan ideal Stirling cycle.

FIG. 11 is a P–V diagram of an ideal Stirling cycle.

FIG. 12 is a P–V diagram of an actual Stirling cycle.

FIG. 13 is a schematic view of a conventional Rankine system that uses are-heating cycle.

FIG. 14 is a sectional view of a steam engine including a scroll-typeexpander according to a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be described indetail with reference to the accompanying drawings.

Referring to FIG. 2, a scroll-type expander 10 according to a preferredembodiment of the present invention includes stationary scroll members13 and orbiting scroll members 15 provided within a housing 12, and itperforms expansion of an working fluid flowing into the scroll-typeexpander 10 then expels the same from the housing 12.

The housing 12 includes a heating surface to an outside; two inflowopenings 27 to a center area that act as openings for the working fluid,the inflow openings 27 being provided at upper and lower areas; and anexhaust opening 23 that allows the exhaust of the working fluid tooutside the housing 12.

The stationary scroll members 13 are fixed to an inner surface of thehousing 12 and extend from the center area of the housing 12 outwardlyin a spiral shape. A pair of the stationary scroll members 13 areprovided in an opposing configuration. A center of the stationary scrollmembers 13 corresponds to the inflow openings 27 of the housing 12.

The orbiting scroll members 15 are meshed with stationary scroll members13 within the housing 12, and they also extend from the center area ofthe housing 12 outwardly in a spiral shape. The orbiting scroll members15 are orbiting along a predetermined orbiting radius to continuouslyexpand working fluid entering the housing 12. A pair of the orbitingscroll members 15 is mounted between the pair of the opposing stationaryscroll members 13, with one orbiting scroll member 15 being meshed withone stationary scroll member 13.

Heating chambers 17 are provided to an outer circumference of thehousing 12. The heating chambers 17 supply heat to inside the housing 12when working fluid is expanded by the motion of the orbiting scrollmembers 15.

Heat pipes (not shown) may be provided in the heating chambers 17 sothat there is sufficient heat transfer and uniform temperaturedistribution. The heat pipes are able to transmit large amounts of heatby the low temperature difference as a result of latent heat.

Pre-heating pipes 25 are connected to the inflow openings 27 and extendinto the heating chambers 17. The pre-heating pipes 25 pass through theheating chambers 17 so that the working fluid entering the heatingchambers 17 may absorb heat.

Further, a plurality of heating pins 19 are formed to an externalheating surface of the housing 12 that is located within the heatingchambers 17. The heating pins 19 increase the heat transfer rate to thehousing 12.

Drive shafts 29 are connected to the orbiting scroll members 15 to drivethe same. Two of the drive shafts 29 are connected to both ends of theorbiting scroll members 15. A power transmission shaft 32 is connectedto one of the drive shafts 29 to enable the transmission of power tooutside the scroll-type expander 10. A bearing assembly 34 is mountedwhere the drive shafts 29 are connected to undergo rotation.

Further, a seal 36 is provided at each area of connection of the driveshafts 29. The seal 36 prevents leakage of lubrication oil. Also, aninsulating material 38 is formed between the bearing assemblies 34 andthe housing 12 to prevent overheating of the bearing assemblies 34.

Working fluid supplied through the pre-heating pipes 25 undergoes aprimary heating process while passing through the pre-heating pipes 25,and is supplied to inside the housing 12 through the inflow openings 27.The working fluid is then slowly expanded while passing between theorbiting scroll members 15 and the stationary scroll members 13. Duringthis process, the working fluid is re-heated by the effective supply ofheat of the wide heating surface of the housing 12 and the scroll wrapssuch that a highly efficient expansion that approaches isothermalexpansion is realized. The working fluid expanded in this manner isexhausted to outside the housing 12 through the exhaust opening 23.

When the temperature of the scroll-type expander 10 is lower than thetemperature of the supplied operational fluid, the scroll-type expander10 of the preferred embodiment of the present invention may also be usedas a scroll-type expander of a refrigerator that absorbs heat in thescroll-type expander 10 driven by external power.

With reference to FIG. 3, a basic structure of a scroll heat exchangesystem 100 according to a first preferred embodiment of the presentinvention includes a scroll-type compressor 112, a scroll-type expander132, and a regenerator 120. The scroll-type compressor 112 and thescroll-type expander 132 are interconnected through a first connector121 and a second connector 123.

The scroll-type compressor 112 includes a stationary scroll member 114and a orbiting scroll member 116 provided within a housing 113, and actsto compress working fluid that enters the scroll-type compressor 112 andexhaust the compressed working fluid through a center area. The housing113 includes one working fluid inflow opening at an outer area and oneworking fluid exhaust opening at the center area, and is otherwisesealed from the outside. The stationary scroll member 114 is fixedwithin the housing 113 and is extended from the center area of thehousing 113 outwardly in a spiral shape. The orbiting scroll member 116is meshed with the stationary scroll member 114 within the housing 113,and also extends from the center area of the housing 113 outwardly in aspiral shape. The orbiting scroll member 116 is orbiting along apredetermined orbiting radius in the space made with the stationaryscroll member 114 to continuously compress working I fluid entering thehousing 113.

A refrigerating section 118 is formed around an outer circumference ofthe housing 113 that surrounds the scroll-type compressor 112. Thecooling section 118 allows for heat generated when working fluid iscompressed to be expelled outwardly. To realize this, the housing 113has a heat radiation surface to an outer area thereof.

The scroll-type expander 132 includes a stationary scroll member 134 anda orbiting scroll member 136 provided within a housing 133, and acts toexpand working fluid that enters the scroll-type expander 132 andexhaust the expanded working fluid. The housing 133 includes one workingfluid inflow opening at a center area and one working fluid exhaustopening at an outer area, and is otherwise sealed from the outside. Thestationary scroll member 134 is fixed within the housing 133 and isextended from the center area of the housing 133 outwardly in a spiralshape. The orbiting scroll member 136 is meshed with the stationaryscroll member 134 within the housing 133 and also extends from thecenter area of the housing 133 outwardly in a spiral shape. The orbitingscroll member 136 is orbiting along a predetermined orbiting radius inthe space made with the stationary scroll member 134 to continuouslyexpand working fluid entering the housing 133.

A heating section 138 is formed around an outer circumference of thehousing 133 that surrounds the scroll-type expander 132. The heatingsection 138 allows heat to be supplied during expansion of workingfluid, and to realize this, the housing 133 has a heating surface to anouter area thereof.

Each of the orbiting scroll members 116 and 136 of the scroll-typecompressor 112 and the scroll-type expander 132, respectively, areconnected to a driver (not shown) so that the orbiting scroll members116 and 136 may be orbiting.

As described above, the scroll-type compressor 112 and the scroll-typeexpander 132 are interconnected through the first connector 121 and thesecond connector 123. In more detail, the first connector 121interconnects the working fluid exhaust and inflow openings at the outerareas of the scroll-type compressor 112 and the scroll-type expander132, while the second connector 123 interconnects the working fluidexhaust and inflow openings at the center areas of the scroll-typecompressor 112 and the scroll-type expander 132.

Heat exchange is realized in the regenerator 120 by the first and secondconnectors 121 and 123 structured in this manner. The first and secondconnectors 121 and 123 pass through the regenerator 120 in a stateadjacent to one another to realize heat exchange between the workingfluid passing through the first and second connectors 121 and 123.

The working fluid is compressed in the scroll-type compressor 112 thenexhausted through the exhaust opening at the center area of thescroll-type compressor 112, passed through the regenerator 120 via thesecond connector 123, then supplied through the inflow opening at thecenter area of the scroll-type expander 132. The working fluid thenundergoes expansion in the scroll-type expander 132, is exhaustedthrough the exhaust opening at the outer area of the scroll-typeexpander 132, passed through the regenerator 120 via the first connector121, then is supplied through the inflow opening at the outer area ofthe scroll-type compressor 112. This process is repeated to realizecirculation of the working fluid through the heat exchange system 100.

With reference to FIG. 4, a cooler 125 and a heater 127 may be furtherincluded in the scroll heat exchange system 100 according to the firstembodiment of the invention.

The cooler 125 is connected to the operational fluid inflow openingprovided to the outer area of the scroll-type compressor 112, and actsto cool the working fluid that is supplied to the scroll-type compressor112 after passing through the regenerator 120. The heater 127 isconnected to the working fluid exhaust opening provided to the centerarea of the scroll-type expander 132, and acts to heat the working fluidthat is supplied to the scroll-type expander 132 after passing throughthe regenerator 120.

When a temperature of the scroll-type expander 132 is higher than atemperature of the scroll-type compressor 112, the scroll heat exchangesystem 100 operates as an engine such that heat is received in thescroll-type expander 132 and heat is rejected from the scroll-typecompressor 112 in the manner of a Stirling engine. Further, heat istransferred from the working fluid of after expansion to the workingfluid of after compression, and power is output through a driver.

On the other hand, if the temperature of the scroll-type expander 132 islower than the temperature of the scroll-type compressor 112, the scrollheat exchange system 100 operates as a refrigerator such that externalpower is received through the driver and heat is received from thescroll-type expander 132 and heat is output from the scroll-typecompressor in the manner of a Stirling refrigerator. Also, heat istransferd from the working fluid of after compression to the workingfluid of after expansion.

FIG. 5 is a sectional view of a scroll heat exchange system according toa second embodiment of the present invention.

With reference to the drawing, a scroll heat exchange system 140according to a second preferred embodiment of the present invention isbasically the same in structure to the scroll heat exchange system 100according to the first preferred embodiment of the present invention.However, a pair of stationary scroll members 143 and a pair of orbitingscroll members 145 are provided in a housing 142 of a scroll-typecompressor 141, and a pair of stationary scroll members 153 and a pairof orbiting scroll members 155 are provided in a housing 152 of thescroll-type expander 151 such that an upsetting moment is not generated.

A plurality of cooling pins 149 are formed to an external surface of thehousing 142 of the scroll-type compressor 141, and a plurality ofheating pins 159 are formed to an external surface of the housing 152 ofthe scroll-type expander 151 such that cooling and heating are betterperformed.

The orbiting scroll members 145 and 155 of the scroll-type compressor141 and the scroll-type expander 151, respectively, are each connectedto two drive shafts 165 to drive the same. A first drive shaft section165 a connected to the orbiting scroll members 145 of the scroll-typecompressor 141 and a second drive shaft section 165 b connected to theorbiting scroll members 155 of the scroll-type expander 151 are 180° outof phase. Such a configuration is used to minimize unbalancing caused byrotational force.

The two drive shafts 165 are connected by a belt or chain to rotate inunison. Also, the drive shafts 165 transmit power to the outside througha power transmission shaft 167 that extends outwardly from the scrollheat exchange system 140. A bearing assembly 169 is mounted where thedrive shafts 165 are connected to undergo rotation.

In the heat exchange system 140 according to the second preferredembodiment of the present invention, working fluid is additionallycooled by passing through the regenerator 160 and cooling chambers 147.Further, the working fluid flows into the scroll-type compressor 141through the first connector 161 to be compressed by the motion of theorbiting scroll members 145. During compression, the working fluid isfurther cooled by the cooling pins 149 formed on the housing 142 in thearea of the same corresponding to where the cooling chambers 147 areformed.

The working fluid compressed in this manner passes through theregenerator 160 through the second connector 162 to realize heatexchange with the high temperature working fluid passing through thefirst connector 161, thereby being heated. Next, this working fluidpasses through heating chambers 157 to be further heated, then issupplied to inside the scroll-type expander 151 to be expanded whileacting against the orbiting scroll members 155. During expansion, theworking fluid is further heated by the heating pins 159 formed on thehousing 152 in the area of the same corresponding to where the heatingchambers 157 are formed.

The working fluid expanded in this manner again passes through theregenerator 160 via the first connector 161 to realize heat exchangewith the low temperature working fluid passing through the secondconnector 162, thereby being cooled. Next, this working fluid issupplied to inside the scroll-type compressor 141 to complete the cycle.

The upper and lower cooling chambers 147 of the scroll-type compressor141 are interconnected, and the upper and lower heating chambers 157 ofthe scroll-type expander 151 are interconnected. Further, the workingfluids exhausted through upper and lower center areas of the scroll-typecompressor 141 are combined for supply to the regenerator 160, and theworking fluids supplied to the scroll-type expander 151 from theregenerator 160 are also combined.

FIG. 6 is a schematic view of a scroll heat exchange system according toa third embodiment of the present invention.

With reference to the drawing, in a heat exchange system according to athird embodiment of the present invention, a center scroll-typecompressor 172 is provided to a middle area of the system. Also, a firstscroll-type expander 174 of a higher temperature than the centerscroll-type compressor 172 is connected to one side of the same, and asecond scroll-type expander 176 of a lower temperature than thescroll-type compressor 172 is connected to another side of the same. Theheat exchange system structured in this manner may be used as a Stirlingrefrigerator driven by Stirling engine.

That is, the combination of the high temperature first scroll-typeexpander 174 and the scroll-type compressor 172 operates as a Stirlingengine, and the combination of the low temperature second scroll-typeexpander 176 and the scroll-type compressor 172 operates as a Stirlingrefrigerator.

Such a structure is made possible by the joint use of the firstscroll-type expander 174 and the second scroll-type expander 176 bothhaving inflow and exhaust openings for working fluid of the scroll-typecompressor 172. Accordingly, working fluid is compressed in thescroll-type compressor 172 then exhausted through an exhaust opening ofa center area. Part of the working fluid passes through a secondconnector 182 then through a first regenerator 185, after which theworking fluid flows into a center area inflow opening of the firstscroll-type expander 174 to be expanded therein. The working fluid isthen exhausted through an exhaust opening of an outer circumference,passed through a first connector 181 and through the first regenerator185, and flowed into an inflow opening of an outer circumference of thescroll-type compressor 172 to thereby realize circulation through thesystem. The other part of the working fluid passes through a fourthconnector 184 and through a second regenerator 186 to flow into aninflow opening of a center area of the second scroll-type expander 176to be expanded therein. The working fluid is then exhausted through anexhaust opening of an outer circumference, passed through a thirdconnector 183 and through a second regenerator 186, and flowed into aninflow opening of an outer circumference of the scroll-type compressor172 to thereby realize circulation through the system.

By jointly using the scroll-type compressor for the Stirling engine andStirling refrigerator, a compact structure is realized for the Stirlingrefrigerator driven by Stirling engine. Also, since a power remainingafter refrigerator driving may be used to generate electric power usinga generator, a system that realizes both air conditioning and electricpower generation may be realized.

FIG. 7 is a schematic view of a scroll assembly connected to a bypassline according to a preferred embodiment of the present invention.

In the conventional control method for a reciprocating Stirlingapparatus, although there are internal working gas pressure changes,dead volume control, and compression ratio changes as a result of strokecontrol, the entire apparatus is complicated and high in cost. Withreference to FIG. 7, in a control method for a Stirling cycle apparatususing a scroll apparatus, compression capacity is controlled bycontrolling a bypass line 193 at a center compression area of astationary scroll member 191 of a scroll-type compressor. As a result,compression amounts are easily controlled. Engine control is thereforequickly and effectively realized.

The center compression area is positioned a predetermined distance froma center area of the scroll-type compressor. Further, the bypass line193 is formed communicating a connector connected to the center area ofthe scroll-type compressor and the center compression area. A controlvalve 195 is provided on the bypass line 193 to control the amount offluid that is bypassed.

FIG. 14 is a sectional view of a steam engine including a scroll-typeexpander according to a preferred embodiment of the present invention.

With reference to the drawing, in addition to a scroll-type expander410, the steam engine includes a heat exchanger 440, a condenser 441, astorage tank 443, and a pump 445.

An exhaust opening 423 of the scroll-type expander 410 is connected tothe heat exchanger 440 such that high temperature working fluid expandedin and exhausted from the scroll-type expander 410 passes through theheat exchanger 440. The heat exchanger 440 is also connected to thecondenser 441.

Working fluid passed through the heat exchanger 440 flows into thecondenser 441 to be condensed therein. The condenser 441 is connectedalso to the storage tank 443 such that the working fluid passed throughthe condenser 441 is temporarily stored in the storage tank 443. Thestorage tank 443 is connected to a pump 445 and acts as a gas-waterseparator to increase a compression efficiency of the pump 445 and toreplenish the working fluid.

The pump 445 acts to pressurize the working fluid supplied from thestorage tank 443. The pump 445 is also connected to the heat exchanger440.

The working fluid pressurized in the pump 445 is heated by receivingheat from the high temperature working fluid exhausted from thescroll-type expander 410 while passing through the heat exchanger 440.The working fluid heated in this manner is supplied to the scroll-typeexpander 410 through a pre-heat pipe 425.

The steam engine having the scroll-type expander structured as in theabove operates identically to the steam turbine Rankine system that usesa regeneration cycle and an infinite stages re-heating cycle.

Although preferred embodiments of the present invention have beendescribed in detail hereinabove, it should be clearly understood thatmany variations and/or modifications of the basic inventive conceptsherein taught which may appear to those skilled in the present art willstill fall within the spirit and scope of the present invention, asdefined in the appended claims.

1. A scroll-type expander, comprising: a sealed housing having a heating surface to an outside area, and including at least one of each of an inflow opening and an exhaust opening at both a center area and a circumferential area; at least a stationary scroll member fixed within the housing and extending from the center area of the housing outwardly in a spiral shape; at least an orbiting scroll member meshed with the stationary scroll member within the housing and extending from the center area of the housing outwardly in a spiral shape, the orbiting scroll member being orbiting along a predetermined orbiting radius to continuously expand working fluid entering the housing; heating chamber provided to an outer circumference of the housing and which supply heat when working fluid is expanded by the motion of the orbiting scroll member; drive shafts connected to the orbiting scroll member to drive the orbiting scroll member; and a pre-heating pipe connected to the working fluid inflow opening of the center area of the housing and extending into the heating chambers to pass through the heating chambers so that the working fluid entering the heating chambers may absorb heat.
 2. The scroll-type expander of claim 1, further comprising heat pipe connected to the heating chambers and able to transmit large amounts of heat by a low temperature difference as a result of latent heat.
 3. The scroll-type expander of claim 1, further comprising a plurality of heating pins formed to the external heating surface of the housing that is located within the heating chambers.
 4. The scroll-type expander of claim 1, further comprising a power transmission shaft connected to an outside of one of the drive shafts to enable the transmission of power to outside the scroll-type expander.
 5. The scroll-type expander of claim 1, wherein the orbiting scroll member is connected to at least two of the drive shafts to be driven by the drive shafts.
 6. The scroll-type expander of claim 1, wherein a pair of the stationary scroll members are provided opposing one another in the housing, and a pair of the orbiting scroll members are provided meshed with the stationary scroll members.
 7. The scroll-type expander of claim 1, wherein a shaft seal is provided at each area of connection of the drive shafts to the housing, the seal providing a lubricated seal.
 8. The scroll-type expander of claim 1, wherein a bearing assembly is mounted where the drive shafts are connected to the housing, and an insulating material is provided where the drive shafts are connected to the housing to prevent overheating of the bearing assemblies and to prevent heat from escaping from inside the housing.
 9. A scroll heat exchange system, comprising: a scroll-type compressor including a sealed housing having a heat radiation surface and having at least one of each of an working fluid inflow opening and an exhaust opening at both a center area and a circumferential area, a stationary scroll member fixed within the housing and extending from the center area of the housing outwardly in a spiral shape, and a orbiting scroll member meshed with the stationary scroll member within the housing and extending from the center area of the housing outwardly in a spiral shape, the orbiting scroll members being orbiting along a predetermined orbiting radius to continuously compress working fluid entering the housing; a scroll-type expander including a sealed housing having a heating surface and having at least one of each of an working fluid inflow opening and an exhaust opening at both a center area and a circumferential area, a stationary scroll member fixed within the housing and extending from the center area of the housing outwardly in a spiral shape, and a orbiting scroll member meshed with the stationary scroll member within the housing and extending from the center area of the housing outwardly in a spiral shape, the orbiting scroll members being orbiting along a predetermined orbiting radius to continuously expand working fluid entering the housing; a driver connected to each of the orbiting scroll members of the scroll-type compressor and the scroll-type expander to drive the orbiting scroll members; a first connector interconnecting the working fluid exhaust and inflow openings at the outer areas of the scroll-type compressor and the scroll-type expander; a second connector interconnecting the working fluid exhaust and inflow openings at the center areas of the scroll-type compressor and the scroll-type expander; a regenerator through which the first and second connectors pass in a state adjacent to one another to realize heat exchange between the working fluid passing through the first and second connectors; and working fluid compressed in the scroll-type compressor, exhausted through the exhaust opening at the center area of the scroll-type compressor, passed through the regenerator via the second connector, then supplied through the inflow opening at the center area of the scroll-type expander, after which the working fluid undergoes expansion in the scroll-type expander, is exhausted through the exhaust opening at the outer area of the scroll-type expander, passed through the regenerator via the first connector, and supplied through the inflow opening at the outer area of the scroll-type compressor to thereby realize circulation of the working fluid through the heat exchange system.
 10. The scroll heat exchange system of claim 9, further comprising a cooling section formed around an outer circumference of the housing that surrounds the scroll-type compressor such that heat generated when working fluid is compressed is expelled outwardly, and a heating section formed around an outer circumference of the housing that surrounds the scroll-type expander such that heat is supplied during expansion of working fluid.
 11. The scroll heat exchange system of claim 9, further comprising a cooling connected to the working fluid inflow opening provided to the outer area of the scroll-type compressor and acting to cool the working fluid that is supplied to the scroll-type compressor after passing through the regenerator, and a heater connected to the working fluid exhaust opening provided to the center area of the scroll-type expander and acting to heat the working fluid that is supplied to the scroll-type expander after passing through the regenerator.
 12. The scroll heat exchange system of claim 9, further comprising a plurality of heat transfer pins that are formed to outer surfaces of the housing of the scroll-type compressor and the housing of the scroll-type expander, the heat transfer pins enabling easier heat absorption and heat rejection.
 13. The scroll heat exchange system of claim 9, further comprising a bypass line communicating an area between a center compression area of a predetermined distance from the center area of the housing and the connector connected to the working fluid exhaust opening of the center area, and further comprising a control valve mounted on the bypass line to control the amount of fluid that is bypassed to vary compression amounts.
 14. The scroll heat exchange system of claim 9, wherein the system operates as an engine when a heat of a temperature higher than a temperature of the scroll-type compressor is supplied to the scroll-type expander, and power is output from the drivers connected to the scroll-type expander and the scroll-type compressor.
 15. The scroll heat exchange system of claim 9, wherein the system operates as a refrigerator when power is input to the drivers connected to the scroll-type expander and the scroll-type compressor, and a heat of a temperature lower than a temperature of the scroll-type compressor is absorbed in the scroll-type expander.
 16. The scroll heat exchange system of claim 9, wherein the orbiting scroll members of the scroll-type compressor and the scroll-type expander are each connected to two drive shafts to be driven by the drive shafts.
 17. The scroll heat exchange system of claim 16, wherein the drive shafts connected to the orbiting scroll members of the scroll-type compressor maintain a phase difference of 180° with the drive shafts connected to the orbiting scroll members of the scroll-type expander.
 18. A scroll heat exchange system, comprising: a first scroll-type expander including a sealed housing having a heating surface and having at least one of each of a working fluid inflow opening and an exhaust opening at both a center area and a circumferential area, a stationary scroll member fixed within the housing and extending from the center area of the housing outwardly in a spiral shape, and an orbiting scroll member meshed with the stationary scroll member within the housing and extending from the center area of the housing outwardly in a spiral shape, the orbiting scroll members being orbiting along a predetermined orbiting radius to continuously expand working fluid entering the housing; a scroll-type compressor including a sealed housing having a heat radiation surface and having at least one of each of the working fluid inflow opening and an exhaust opening at both a center area and a circumferential area, a stationary scroll member fixed within the housing and extending from the center area of the housing outwardly in a spiral shape, and an orbiting scroll member meshed with the stationary scroll member within the housing and extending from the center area of the housing outwardly in a spiral shape, the orbiting scroll members being orbiting along a predetermined orbiting radius to continuously compress working fluid entering the housing; a second scroll-type expander including a sealed housing having a heating surface and having at least one of each of a working fluid inflow opening and an exhaust opening at both a center area and a circumferential area, a stationary scroll member fixed within the housing and extending from the center area of the housing outwardly in a spiral shape, and an orbiting scroll member meshed with the stationary scroll member within the housing and extending from the center area of the housing outwardly in a spiral shape, the orbiting scroll members being orbiting along a predetermined orbiting radius to continuously expand working fluid entering the housing; a driver connected to each of the orbiting scroll members of the scroll-type compressor and the scroll-type expanders to drive the orbiting scroll members; a first connector interconnecting the working fluid exhaust and inflow openings at the outer areas of the scroll-type compressor and the first scroll-type expander; a second connector interconnecting the working fluid exhaust and inflow openings at the center areas of the scroll-type compressor and the second scroll-type expander; a first regenerator through which the first and second connectors pass in a state adjacent to one another to realize heat exchange between the working fluid passing through the first and second connectors; a third connector interconnecting the working fluid exhaust and inflow openings at the outer areas of the scroll-type compressor and the second scroll-type expander; a fourth connector interconnecting the working fluid exhaust and inflow openings at the center areas of the scroll-type compressor and the second scroll-type expander; a second regenerator through which the third and fourth connectors pass in a state adjacent to one another to realize heat exchange between the working fluid passing through the third and fourth connectors; and working fluid compressed in the scroll-type compressor, exhausted through the exhaust opening at the center area of the scroll-type compressor, then part of the working fluid is passed through the first regenerator via the second connector, then supplied through the inflow opening at the center area of the first scroll-type expander, after which the working fluid undergoes expansion in the first scroll-type expander, is exhausted through the exhaust opening at the outer area of the scroll-type expander, passed through the first regenerator via the first connector, and supplied through the inflow opening at the outer area of the scroll-type compressor, and the remaining part of the working fluid is passed through the second regenerator via the fourth connector, then supplied through the inflow opening at the center area of the second scroll-type expander, after which the working fluid undergoes expansion in the second scroll-type expander, is exhausted through the exhaust opening at the outer area of the second scroll-type expander, passed through the second regenerator via the third connector, and supplied through the inflow opening at the outer area of the scroll-type compressor to thereby realize circulation of the operational fluid through the heat exchange system, wherein the first scroll-type expander and the scroll-type compressor may operate as an engine, and the second scroll-type expander and the scroll-type compressor may operate as a refrigerator.
 19. A steam engine, comprising: a scroll-type expander including a sealed housing having a heating surface and having at least one of each of an working fluid inflow opening and an exhaust opening at both a center area and a circumferential area, a stationary scroll member fixed within the housing and extending from the center area of the housing outwardly in a spiral shape, an orbiting scroll member meshed with the stationary scroll member within the housing and extending from the center area of the housing outwardly in a spiral shape, the orbiting scroll members being orbiting along a predetermined orbiting radius to continuously expand working fluid entering the housing, heating chambers provided to an outer circumference of the housing and which supply heat when working fluid is expanded by the motion of the orbiting scroll members, and drive shafts connected to the orbiting scroll members to drive the scroll members; a heat exchanger through which high temperature working fluid expanded in the scroll-type expander and exhausted from the scroll-type expander passes; a condenser for condensing the working fluid passing through the heat exchanger; a storage tank for storing the working fluid passing through the condenser; and a pump for pressurizing the working fluid passing through the storage tank, wherein the working fluid pressurized in the pump is circulated by again passing through the heat exchanger to receive heat from high temperature working fluid, to be heated. 